The heating and cooling for the building will consist of geothermal ground-coupled, water-cooled heat pumps. This system will include 30 wells located in the parking lot. Each well will be approximately 305 feet.

August 2002
Controlling the run off from well drilling.

July 28, 2002
Drilling the wells.

Background on Geothermal Energy
- by Anna LaRue, GBC summer intern

Geothermal energy is the heat stored in the Earth’s crust. The most common form of geothermal utilization in northeast Ohio is shallow ground geothermal energy. The upper ten feet of the Earth’s surface maintains general temperatures between 50°F and 60°F and can be tapped by geothermal heat pumps in order to heat and cool buildings. A geothermal heat pump system generally consists of a heat exchanger (a system of pipes buried in the shallow ground near the building), a heat pump, and an air delivery system (ductwork). Geothermal heat pumps can also be called ground-source or water-source heat pumps. The ground heat exchanger is made up of a closed-loop or open-loop system. The closed-loop system is more common, in which high density with an antifreeze/water solution that acts as a heat exchanger. The ductwork distributes heated or cooled air throughout the building. The air handler, containing the indoor coil and fan, moves the building’s air through the heat pump for heating and cooling.

Geothermal heat pumps do not create heat; they just move it from one area to another. In the winter, the heat pump extracts heat from the heat exchanger in the ground; in the summer, heat from the building is pumped into the heat exchanger for cooling. Because the system can be used for both heating and cooling, it eliminates the need for separate heating and cooling systems and uses less electricity. A geothermal heating system has other side benefits: a “desuperheater” can transfer excess heat from the heat pump to the hot water tank, often providing free hot water in the summer, and reduced water heating costs in the winter.

There are four types of ground loop systems, three of which (horizontal, vertical, and pond/lake) are closed-loop systems. The fourth type is open-loop. Different systems are best for different locations and conditions.

Closed-Loop Systems

Horizontal
This requires trenches four feet deep, with the most common layouts using either two pipes, one buried at six feet and one at four feet, or two pipes next to each other five feet deep in a two-foot wide trench. The SlinkyTM method of looping pipe allows for more pipe in a shorter trench.

Vertical
Vertical loops are often used where the soil is too shallow for trenching or where the amount of land required for a horizontal system is not available. In this system, 4-inch vertical holes are drilled about 20 feet apart and 100 to 400 feet deep. A loop of pipe goes into each of these hole and connected horizontally to a heat pump.

Pond/Lake
For this type of installation, a supply line is run underground to the water and coiled at least 8 feet under the surface to inhibit freezing. The pond must meet certain volume and depth standards.

Open-Loop Systems

This type of system uses the water from a well or body of water as the fluid that circulates through the geothermal heat pump system. After being pumped through the system, the water returns to the well or the body of water.